The goal of this project is to show that compositional streamline simulation (CSLS) has very high potential for the simulation of (near) miscible gas injection processes. In this project, researchers are extending and improving a novel and fully adaptive compositional streamline simulator CSLS to three-phase flows. The goal is to increase its computational efficiency so that it will be suitable for use in industry and laboratories for the study of realistic reservoir and production scenarios for a wide variety of gas injection and CO2 sequestration projects. The simulator development is supported by an experimental program designed to improve understanding of three-phase flows, which could lead to improved mathematical models for three-phase relative permeability functions.